1. Field of the Invention
This invention relates to crop cultivation and, more particularly, to a system for automatically introducing seedlings into a controlled environment, controllably conveying the seedlings through the controlled environment as treatment is effected thereon, and discharging the matured seedlings from the system.
2. Background Art
A multitude of crops are conventionally cultivated in the controlled environment of a greenhouse. Exemplary of the types of crop seedlings that are grown in this fashion are vegetables, root crops, fruits, petal-bearing plants, etc.
Heretofore, cultivation of these various crops in greenhouses has been accomplished by five different techniques: 1) a floor installation system; 2) a stationary bed system; 3) a movable bed system; 4) a chain conveying movable system; and 5) a special bed system. The prior systems and their various drawbacks will be explained below.
In the floor installation systems, master boxes, generally constructed from wood, are arranged in square or rectangular blocks directly on the floor of the greenhouse. A representative block of the master boxes may consist of ten such boxes. Within each of the master boxes are a plurality of individual plastic pots, typically on the order of 20, which contain the seedlings. The master boxes must be lifted and transported manually by the greenhouse operators/laborers.
One of the Principal drawbacks with the floor installation systems is that they are very inefficient spacewise. For the seedlings to be accessible to the greenhouse operator, as to effect treatment thereof such as fertilizing and watering, it is necessary for paths to be provided around the boxes. Consequently, a substantial area of the otherwise usable greenhouse floor is dedicated solely to providing a pathway for the greenhouse operator/laborer tending to the growing seedlings.
A further problem with the floor installation systems is that they are normally completely manual systems. That is, the greenhouse operator/laborer manually sets up the boxes with the seedlings, conveys the boxes to different parts of the greenhouse at different stages of maturity for the seedlings, and manually transports the boxes, one by one, out of the greenhouse after the seedlings have adequately matured. Because the boxes are placed on the greenhouse floor, the operator is required to lean over to grasp and raise the boxes. Back pain and back injury for the greenhouse operators/laborers is common.
A still further problem with the floor installation systems is that their effective operation requires a large labor force. It is a labor intensive process to plant the seeds, move the seedlings, and effect conveyance of the boxes to the various parts of the greenhouses in which they are separately treated.
In the bed-type systems, the individual wooden boxes containing the pots are placed on a table, as opposed to the previously described floor installation system. The principal advantage of the table is that the boxes are at a more convenient working height and need not be elevated from ground level to effect conveyance thereof.
However, all of the other drawbacks of the floor installation system are present, i.e. the large space requirements, slow operation, inconvenience of manual setup and movement of the seedlings and the requirement of a large labor force.
The movable bed systems are similar to the table bed systems, described above, with the exception that groups of rollers are arranged on the table tops which allow the individual wooden boxes to be more easily slid along the tabletops by rotation of the rollers. This arrangement facilitates repositioning of the individual boxes and readily allows a working space to be developed around the individual boxes by simply relatively shifting the boxes through the roller system.
However, while movement of the individual boxes is facilitated, the entire system remains manual. Further, movement of the boxes onto the table, of f of the table to separate locations in the greenhouse, and out of the greenhouse, is effected manually so that the system, while easier to operate than the above described systems, remains labor intensive and quite inefficient in terms of time and space.
In the chain conveyor systems, conveyors are arranged serially to transport seedlings through germinating greenhouses and cultivating greenhouses. A cultivating tray is contained in a case which is translated at slow speeds in a substantially straight path as the conveyor is operated.
In the special bed systems, seedlings are planted in openings within perforated panels, with the perforations arranged stereoscopically in a crescent shape. Nutrient solution is sprayed onto the seedlings to effect cultivation thereof.
The chain conveyor and special bed systems both require a substantial amount of manual labor.
All of the above systems require that the seedlings, at a certain stage of development, be spaced, each from the other, to avoid intermingling of the seedlings that would detrimentally alter the growth process. In each of the above systems, this process must be carried out manually.
The quality of the various crops is dependent heavily on the growing conditions. Crop quality varies depending on the amount of nutrients added, the condition of the air, the amount of sunshine, the ambient temperature and the amount of moisture to which the crops are subjected. Certain of these conditions are inherently different from one location to the next in a greenhouse. Consequently, with the above described systems, there typically is a significant difference in the quality of the crops from one location to the next in the greenhouse. This is a particularly undesirable problem that is contended with in the above prior art mass production systems.